Dc-dc converter

Abstract

A DC-DC converter includes a voltage input module receiving an input voltage from an exterior power supply, a voltage transforming module connected with the voltage input module for transforming the input voltage into a proper output voltage, a voltage output module connected with the voltage transforming module for supplying the proper output voltage to an exterior electric appliance, a first detecting module connected with the voltage output module for detecting an output current of the voltage output module and sending a corresponding current signal, a second detecting module connected with the voltage output module for detecting the output voltage of the voltage output module and sending a corresponding voltage signal, and a control module for receiving and analyzing the corresponding current and voltage signals and then generating a corresponding control signal so as to control the output voltage of the voltage transforming module for protecting the electric appliance.

1 . A DC-DC converter, comprising:
 a voltage input module receiving an input voltage from an exterior power supply;   a voltage transforming module connected with the voltage input module for transforming the input voltage into a proper output voltage;   a voltage output module connected with the voltage transforming module for supplying the proper output voltage to an exterior electric appliance;   a first detecting module connected with the voltage output module for detecting an output current of the voltage output module and sending a corresponding current signal;   a second detecting module connected with the voltage output module for detecting the output voltage of the voltage output module and sending a corresponding voltage signal; and   a control module for receiving and analyzing the corresponding current and voltage signals sent by the first and second detecting modules and then generating a corresponding control signal so as to control the output voltage of the voltage transforming module for protecting the electric appliance.   
     
     
         2 . The DC-DC converter as claimed in  claim 1 , wherein the first detecting module includes at least three resistance elements, two of which are connected to a positive output terminal and a negative output terminal of the voltage output module, respectively, and another is connected with a reference voltage, other three terminals of the three resistance elements are connected with one another so that the resistance elements can voltage-divide to the output voltage for generating a potential at the connection location of the resistance elements namely the detected current signal, the control module is connected with the connection location of the resistance elements. 
     
     
         3 . The DC-DC converter as claimed in  claim 1 , wherein the control module analyzes the corresponding voltage signal sent by the second detecting module by means of comparing the voltage signal with a default voltage value in the control module. 
     
     
         4 . The DC-DC converter as claimed in  claim 1 , wherein the second detecting module includes a voltage-over protecting circuit capable of preventing the output voltage from being over-high and having a transient voltage suppressor and a resistance element series-connected with each other, another terminal of the transient voltage suppressor is connected with a positive output terminal of the voltage output module, another terminal of the resistance element is connected to a negative output terminal of the voltage output module, the control module is connected with the connection location of the transient voltage suppressor and the resistance element. 
     
     
         5 . The DC-DC converter as claimed in  claim 1 , wherein the voltage transforming module includes a switch element and a transformer, one terminal of a primary winding of the transformer is connected with the voltage input module and the other terminal thereof is connected with the switch element, the voltage output module is connected with a secondary winding of the transformer, the control module is connected with the switch element so as to control a switch state of the switch element according to the control signal and further regulate the output voltage of the transformer according to the switch state. 
     
     
         6 . The DC-DC converter as claimed in  claim 5 , wherein the switch element is an N-channel FET having the drain connected with the primary winding of the transformer, the source connected to ground, and the grid connected to the control module. 
     
     
         7 . The DC-DC converter as claimed in  claim 5 , wherein the voltage transforming module further includes a snubber circuit parallel-connected with the primary winding of the transformer for filtering out additional voltage waves generated by connection and disconnection of the switch element, the snubber circuit includes a capacitor, a first diode series-connected with the capacitor, and a first resistor parallel connected with the capacitor. 
     
     
         8 . The DC-DC converter as claimed in  claim 5 , wherein the DC-DC converter further includes a driving module connected between the switch element and the control module for being controlled by the control module to drive the switch state of the switch element, the driving module includes a triode having the emitter connected to the switch element through a third resistor and the collector connected to ground, the base of the triode is, on one hand, connected to the collector by means of a fourth resistor, and on the other, connected to the emitter through a third diode, the base of the triode is further directly connected with the control module. 
     
     
         9 . The DC-DC converter as claimed in  claim 1 , further comprising a shield having an input portion and an output portion, the input portion showing a structure of car cigar-lighter plug and being electrically connected with the voltage input module, the output portion being a serial interface or a power socket and electrically connected with the voltage output module.